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Chronic Liver Disease
Published in Praveen S. Goday, Cassandra L. S. Walia, Pediatric Nutrition for Dietitians, 2022
Julia M. Boster, Kelly A. Klaczkiewicz, Shikha S. Sundaram
Vitamin A deficiency can manifest as night blindness, xerophthalmia (dry eyes), Bitot spots (white plaques on the conjunctiva), and follicular hyperkeratosis (a rough, raised rash located on the extremities). Ideally, the serum retinol level and retinol to retinol-binding protein molar ratio (retinol:RBP) are used to assess vitamin A status. Serum retinol of <20 μg/dL with a molar ratio of <0.8 indicates vitamin A deficiency.
Optimal Nutrition in Low Birth Weight Infants
Published in Fima Lifshitz, Childhood Nutrition, 2020
Ronald Bainbridge, Reginald Tsang
Similar to vitamin E, the mechanisms of human fetal vitamin A accretion are unknown. Several studies support the hypothesis of active placental transport of vitamin A.42,43 Fetal vitamin A status appears to be well maintained irrespective of maternal vitamin A status. Vitamin A is a lipid soluble vitamin requiring an intact biliary/pancreatic system for optimum digestion. Ingested plant and animal vitamin A sources are hydrolyzed by pancreatic secretions releasing retinol which is absorbed in the small intestine. The mode of absorption is unclear but may be a passive process. After absorption, vitamin A is stored predominantly in the liver from where it is transported to other tissues bound to retinol binding protein (RBP).44 Preterm infants are at increased risk for vitamin A and fat malabsorption secondary to the immaturity of their GI enzymes.1 However, human milk feeding may facilitate vitamin A absorption in these infants.45 The precise serum vitamin A concentration which defines a deficiency state in the preterm infant is unclear. Measurements of serum vitamin A, RBP and vitamin A to RBP molar ratio have all been used to assess vitamin A status43,46 Serum vitamin A concentrations below 10 mcg/dl probably represent vitamin A deficiency.28
Extrahepatic Synthesis of Acute Phase Proteins
Published in Andrzej Mackiewicz, Irving Kushner, Heinz Baumann, Acute Phase Proteins, 2020
Gerhard Schreiber, Angela R. Aldred
Retinol is transported in the blood stream bound to retinol-binding protein. Retinolbinding protein is, itself, bound to transthyretin. Using a genomic DNA fragment containing the exons coding for retinol-binding protein as a probe, extrahepatic expression of the gene for retinol-binding protein was demonstrated95 for choroid plexus, other areas of the brain, and liver by Northern analysis of RNA extracts, as illustrated in Figure 17.
All-Trans Retinoic Acid Prevents the Progression of Gastric Precancerous Lesions by Regulating Disordered Retinoic Acid Metabolism
Published in Nutrition and Cancer, 2022
Hanhan Wu, Didi Zhao, Chen Wang, Daoming Zhang, Min Tang, Shiqing Qian, Lina Xu, Tao Xia, Juanyan Zhou, Guangjun Wang, Yue He, Lei Gao, Wenjun Chen, Li Li, Wanshui Yang, Qihong Zhao, Chuanlai Hu, Anla Hu
As the most biologically active metabolite of vitamin A, retinoic acid (RA) cannot be obtained directly from food but only vitamin A (retinol, retinyl ester, or carotenoids) from food that is metabolized in the body (11). Retinol is delivered to target cells bound to plasma retinol-binding protein (RBP). HoloRBP binds to RBP receptor, stimulated by retinoic acid gene 6 (STRA6) (12, 13). Cellular retinol-binding protein 1 (CRBP1) accepts retinol from STRA6 in the cytoplasm and delivers retinol to membranes, where retinol is either esterified by lecithin retinol acyltransferase (LRAT) to inactive retinyl ester or oxidized by retinol dehydrogenases (RDH) to retinal (14, 15). Retinal is oxidized further to RA by aldehyde dehydrogenases (ALDH) in the cytoplasm or is reduced back to retinol by retinal dehydrogenases in the membranes (14, 16). RA binds to cellular retinol acid-binding protein (CRABP1/2). Most RA is transferred by holoCRABP2 to the nucleus for binding to heterodimers of RA receptors (RARs) and retinoid X receptors (RXRs) in the target nucleus and thereafter triggers the downstream signaling pathways. The remainder is delivered to enzymes by holoCRABP1 for degradation. The clearance of RA is mediated predominantly by cytochrome P450 family 26 enzymes (CYP26). The family consists of three highly conserved enzymes, CYP26A1, CYP26B1, and CYP26C1 (17, 18). In addition, β-carotene is taken up by the cells and cleaved into retinal by β-carotene 15-15′-oxygenase (BCO1). Retinals derived from β-carotene may be oxidized to RA or converted to retinol (19).
Validity and Reliability of a Nutritional Screening Tool (SCAN) in Children Newly Diagnosed with Cancer
Published in Nutrition and Cancer, 2022
Gustavo Cañedo, Laura María Palomino Pérez, Laura Andrea Puerta Macfarland, David Ruano Dominguez, Elvira Cañedo-Villaroya, Beatriz Garcia Alcolea, Luis Madero López, Consuelo Pedrón-Giner
Many patients showed decreased values of prealbumin and retinol-binding protein in blood (Table 3). The low clinical value of these markers has been increasingly emphasized in the literature, defying the widespread use they are given in everyday clinical practice (3). It is frequent to find low values of prealbumin or RBP, probably as a result of inflammation and less as a marker of poor nutrition (38–40). The presence of high ferritin and C-reactive protein levels in our cohort is in line with this mechanism. “At-risk” patients identified by the SCAN tool specifically showed a tendency toward higher levels of inflammation markers. All in all, though bad markers for acute undernutrition, hepatic proteins are being regarded as indicators of morbidity and mortality with patients struggling to meet nutritional requirements and requiring aggressive nutritional support due to sustained inflammation (38, 39).
Combination of podophyllotoxin and rutin modulate radiation-induced alterations of jejunal proteome in mice
Published in International Journal of Radiation Biology, 2020
Sania Bajaj, Syed Imteyaz Alam, Basir Ahmad, Humaira Farooqi, Manju Lata Gupta
Exposure to 9 Gy radiation resulted in upregulation of bimolecular transportation and metabolic pathway related proteins such as alcohol dehydrogenase 6 A (class V), ribonuclease inhibitor, and UMP-CMP kinase in mice jejunum. Retinol-binding protein 2 of the same category upregulated immediately after radiation exposure but decreased significantly at 216 h. It was found upregulated at initial time-points even with G-003M pretreatment but its expression gradually returned to normal at 840 h post-experimentation. Cytoskeleton proteins like tropomyosin alpha-4 chain, tropomyosin alpha-3 chain, gamma-actin, and cofilin-1 were also observed to downregulate after 9 gray IR exposures. Cofilin-1 drastically decreased post 1 h radiation exposure, but tropomyosin alpha chain 3 and 4 showed a gradual decrease till death of the animal. Myosin regulatory light polypeptide 9 (MYL9) increased initially (24 h) but a gradual decrease was observed thereafter to 0.66 ± 0.3-fold post-IR. Radiation mediated decrease in expression of these proteins not just affects the rearrangement of cellular cytoskeleton but also destabilizes their dynamics which severely disbalances cellular homeostasis. The pre-administration of G-003M expressed a positive modulation over these proteins. The tropomyosin proteins and MYL9 revealed a non-significant change in expression even post-IR but cofilin-1 declined initially to 0.57 ± 0.13-fold till 120 h but later enhanced to control level by 840 h.